Apparatus for controlling and modulating engine functions

ABSTRACT

Changes in barometric pressure and/or temperature can adversely affect a number of engine functions. Apparatus is disclosed for controlling and modulating a number of engine functions, including carburetor idle fuel and main fuel supply, fuel enrichment during acceleration and wide open throttle operation, as well as vacuum applied to such vacuum motors associated with the engine as the carburetor choke, the spark advance and automatic transmission shift. Calibration features are provided for establishing a base condition of operation as well as individual calibration of all the various functions listed together with the ability to make base calibration changes by application of an external signal.

United States Patent Brown et al.

[75] Inventors: Morris C. Brown, Florissant; Forrest W. Cook, WebsterGroves, both of Mo.; Ralph E. Kalert, Granite City, 111.; Arthur C.Vollmer, St. Charles; Jerry l-I. Winkley, St. Louis, both of Mo.

[73] Assignee: ACF Industries, Incorporated, New

York, NY.

[22] Filed: Feb. 9, 1973 [21] Appl. No.: 331,286

[52] US. Cl 261/39 A, 123/119 A, 261/69 R [51] Int. Cl. ..F02m1/10 158]Field of Search 123/119 R, 124 A, 124 B;

261/D1G. 2, 39 A, 39 B, 69 R, 121 8,177, 179

[56] References Cited UNITED STATES PATENTS 2,008,143 7/1935 Mock 261/39A 2,230,159 1/1941 Kratzer 123/124 A 2,402,350 6/1946 Silver 26l/DIG. 2

2,631,024 3/1953 Beardsley, 1r. 261/39 A Primary Examiner-Manuel A.Antonakas [57] ABSTRACT Changes in barometric pressure and/ortemperature can adversely affect a number of engine functions. Apparatusis disclosed for controlling and modulating a number of enginefunctions, including carburetor idle fuel and main fuel supply, fuelenrichment during acceleration and wide open throttle operation, as wellas vacuum applied to such vacuum motors associated with the engine asthe carburetor choke, the spark advance and automatic transmissionshift. Calibration features are provided for establishing a basecondition of operation as well as individual calibration of all thevarious functions listed together with the ability to make basecalibration changes by application of an external signal.

4 Claims, 19 Drawing Figures 5 XIEHTED 1 8B5 sezmauw 5 .56

FIGURE 5.

FIGURE 7.

FIGURE I6.

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FIGURE I5. 320

FIGURE 18.

FIGURE 17.

APPARATUS FOR CONTROLLING AND MODULATING ENGINE FUNCTIONS BACKGROUND OFTHE INVENTION There are a number of functions of the internal combustionengine that are affected, usually adversely, by changes in operatingconditions such as barometric pressure, ambient temperature andfrequently one or more temperatures associated with the engine itself.In the case of stationary engines, and other engines operating underessentially constant load conditions, adjustments can be made to achieveefficient operation of the engine under these more or less constantconditions. In the case of the automotive engine, no single set of adjustments are capable of compensating for the constantly changingvariables surrounding the engine.

Among the several engine functions that can be affected by changes inaltitude and temperature, the idle fuel and main fuel systems of theconventional carburetor are very important. These fuel metering systemsare severely affected by changes in altitude; so much so, that with anunmodified carburetor the engine will receive an unnecessarily richmixture whenever there is any great departure from sea level.customarily, this situation has been accepted and/or tolerated with theexception that if an automotive vehicle is normally used at higheraltitudes a permanent change is made to reduce the size of the meteringjet or to install a larger metering rod, or both, and such modificationallows the engine to operate correctly so long as the vehicle is kept atsubstantially the same altitude. If this vehicle is driven to sea levelconditions, then the mixture may be unduly lean. In a somewhat similarmanner, changes in temperature which directly affect the temperature ofthe fuel as well as that of the air entering the carburetor will alsocause undesirable changes in the air/fuel ratio discharged by thecarburetor to the engine. For automotive engines, little has been doneto alleviate these conditions other than the use ofa hot idlecompensator which can admit some additional air to the intake manifoldwhen ambient conditions have exceeded some preselected temperature andthis addition of air without additional fuel has the affect of leaningthe mixture out at the higher ambient temperature. While automotivecarburetors normally have made no compensation for the above-mentionedvariables, many aircraft carburetors over the years have necessarilyembodied altitude compensation. but because of the considerabledifferences in the carburetors used on aircraft with respect to thoseused on automobiles, the overall approach to correcting fuel ratio isnot well suited to that of the automotive carburetor.

Power enrichment is another important carburetor function that isadversely affected by changes in altitude and for which there has beenno compensation provided in commercial carburetors. Power enrichmentcustomarily is provided by opening an auxiliary fuel passage or bymoving a metering element so that additional fuel can enter the mainfuel system. In both cases. the manifold vacuum is applied to one sideof a diaphragm or piston and when manifold vacuum is high only normalfuel quantities are allowed to enter the main fuel system. When manifoldvacuum becomes low then the movable member shifts into another position,thus allowing enrichment fuel to pass into the fuel system. The movablemember (diaphragm or piston) is normally biased by a spring to movetoward the enrichment position and the bias of this spring is overcomeby the manifold vacuum. If the spring is so adjusted that it will causeenrichment whenever manifold vacuum drops below about six inchesmercury, then no enrichment occurs until the engine is heavily loadedand usually a wide-open throttle condition has been reached. On theother hand, when the same vehicle is operated at altitudes of 5,000 feetor more, the power enrichment may come into play even though the engineis relatively lightly loaded. This condition is caused by the fact thatbarometric pressure at altitudes is considerably less than that at sealevel and this reduction in am hient pressure is reflected in the intakemanifold as a lesser degree of manifold vacuum for normal operation.Accordingly, as the engine is increased in its normal loading, thepressure condition necessary for power enrichment may be reached far inadvance of any actual need for the enrichment.

There are other engine and vehicle functions that are also dependentupon manifold vacuum and which functions can be adversely affected bychanges in altitude. One such engine function is the advance and retardof the spark ignition which is normally done by a diaphragm motor.Again, a considerable change in alti tude may cause the diaphragm motorto shift the spark advance at a time when the engine does not requiresuch a shift and this, then becomes an undesirable result. In a similarfashion, some automatic transmissions are equipped with a diaphragmactuated motor for assisting in the shifting of the transmissionmechanism. As is the case of the spark advance, the automatictransmission vacuum motor may come into play or fall out of play at anundesirable operating condition.

BRIEF DESCRIPTION OF THE DRAWING:

FIG. I is a representation of an engine having the compensating unit ofthe invention attached to the carburetor of the engine.

FIG. 2 is a plan view of the interior ofthe compensating unit.

FIG. 3 is a section along the lines of 3-3 of FIG. 2.

FIG. 4 is another section taken along the lines of 4-4 of FIG. 2.

FIG. 5 is a partial section of a carburetor showing the manner ofadmitting air from the compensating unit into the main fuel system of acarburetor.

FIG. 6 is a partial section of a carburetor showing the manner ofintroduction of air into the idle system.

FIG. 7 is a partial sectional view of a carburetor showing a vacuumcontrolled accelerating pump and having attached to said carburetor asecond vacuum controlled device and illustrating a passage for air fromthe compensating unit to the vacuum passage in the carburetor tomodulate vacuum to the respective vacuum motors.

FIG. 8 is a partial plan view of a multibarrel carburetor illustratingthe compensating unit of the invention integrally attached to thecarburetor.

FIG. 9 is a partial section of the carburetor showing the idle fueladjustment screw and the air modulating passage from the compensatingunit.

FIG. 10 illustrates the air passage for passing air from thecompensating unit to the air metering portions of the carburetor of FIG.8.

FIG. 1] illustrates the communication of an air passageway of FIG. 8with the secondary nozzle of the multibarrel carburetor of FIG. 8.

FIG. 12 is a partial section of the main fuel system of the primarybarrels of the carburetor of FIG. 8 illustrating the communication ofthe modulated air from the compensating unit with the main fuel nozzle.

FIG. 13 is another partial section of a carburetor showing the vacuumpiston which raises and lowers a fuel metering rod and illustrating thevacuum passage which is modulated by the compensating unit of theinvention.

FIG. 14 is an elevation view of the compensating unit of FIG. 8 with thecover removed.

FIG. 15 is a sectional view of FIG. 14 with the cover in place.

FIGS. l6, l7, l8 and 19 are details of various construction featuresofthe compensating unit of FIGS. 14 and 15.

BRIEF DESCRIPTION OF THE INVENTION In order to make the compensation forthe various engine and automotive functions described above, there isprovided a compensation unit which can be installed in the vehicle ormade integral with the carburetor as desired and this unit meters airinto the various systems involved in such a manner as to automaticallycompensate for changes in engine operating characteristics caused bychanges in atmospheric pressure andfor temperature.

Basically, the compensation unit includes a capsule which is temperatureand/or barometric sensitive to change its dimensions as the altitude orthe temperature varies. This capsule moves a plate to which are attacheda number of metering elements. One group of metering elements arearranged in such a manner as to increase air flow as the altitudeincreases and also increase air flow as temperature increases. Anothermetering element is arranged to operate in the opposite direction sothat maximum air flow occurs at low altitude and/or temperature and adecreasing quantity of air flows as the altitude and/or temperatureincreases. The first-mentioned group of metering elements provide an airbleed into one or more of the fuel systems of the carburetor to overcomethe tendency toward richness as temperature and altitude increase.Another metering element is adapted to admit larger quantities of air atsea level and standard temperatures with a reduced quantity ofair as thealtitude and/or temperature increases. This last mentioned meteringclement serves to reduce what would normally be a high manifold vacuumapplied to some operative function of the engine at low altitudes andlow temperatures and to reduce the air admitted with changes in thosevariables so that the vacuum actually applied will remain substantiallyconstant, irrespective of any change in altitude or temperature.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 there is shown analtitude and/or temperature compensating unit 10 attached to acarburetor 12 by a plurality of conduits l4, l6, l8 and 20, whichillustrate one realization of the invention. Carburetor 12 is suitablymounted on an intake manifold 13 which delivers the usual air/fuelmixture to an engine 15. Products of combustion are discharged from theengine into an exhaust pipe 17 and thence to a muffler 19 from which theproducts are discharged into the atmosphere. An air cleaner or filter 2]is installed on carburetor 12 so that only clean filtered air isdelivered to the intake of the internal combustion engine.

Referring now to FIGS. 2, 3 and 4, compensating unit 10 is shown ingreater detail. The unit comprises a body portion 22 having a cover 23which cover seals the unit from the atmosphere. Conduit 14, which inthis embodiment may be a rubber hose, is attached to a nipple 24 forconducting clean air to the interior of unit I0. Thus, the interior ofunit It) has air at substantially atmospheric pressure inside it at alltimes. Any deviation from absolute atmospheric pressure will be due toany pressure drop that may occur across the filter element and aircleaner 21. Within housing 22, there is an ambient air conditionresponsive device 30 which, in this instance, is a capsule of thebellows type which is conditioned to have within it a predetermined airpressure which, for barometric or altitude compensation represents ahigh degree of evacuation of the interior of the capsule. Additionally,there may be provided on the interior of capsule 30 a spring 32 which,through proper biasing, makes the capsule responsive to give the desiredmovement for a given change. High evacuation makes the capsule almosttotally responsive to barometric change, while partial evacuation causesthe cap sule to respond to both barometric and temperature change.Accordingly, the spring bias and degree of evacuation will be chosen toachieve predetermined requirements. The base of capsule 30 is secured tothe housing 22 in any convenient manner, in this instance by way of aboss 33. A detent 34 is provided at the upper end of capsule 30 forreceiving an adjustment screw 36 as will be hereinafter described. Aplate 40 is installed in an upper portion of housing 22 and is pivotedat 42 in such a manner that it positions adjustment screw 36 above unit30 so that changes of length in unit 30 occasioned by changes inbarometric pressure and- /or temperature will cause plate 40 to moveupwardly and downwardly about the pivot 42.

A plurality of adjustment screws other than screw 36 are carried byplate 40. These are identified as 44, 46, 48 and 50. Each suchadjustment screw is provided for the purpose of making final adjustmentand calibration of the metering elements and biasing arrangements usedin the device. Screw 44 at its lower extremity contacts a metering pin52 which, by way of conduit I6, controls the quantity of air bled intothe main fuel system. Such bleed air, when increased in quantity servesto diminish the amount of fuel delivered to the carburetor by the mainfuel nozzle. When the bleed air is reduced or cut off, a greaterquantity of fuel is made available through the main nozzle. Metering pin52 is urged in an upward direction by a biasing spring 54. Clean airfrom the interior of housing 22 is admitted into the vicinity ofmetering pin 52 by an air passageway 53 so that as pin 52 rises, thetapered end portion uncovers the air entry passageway to admit air intoconduit I6 and thence, by way of conduit 16 to a passageway 55 in thecarburetor itself, which communicates with a portion of the main fuelsystem and. in this instance, the anti-perk well 56. Air passing intoantiperk well 56 then mixes with the fuel in passageway 57 so that amixture of air and fuel are discharged by nozzle 58 into the boostventuri 60 of the carburetor. The fuel, of course, is supplied from aconstant level fuel bowl 62 and enters that main fuel passage by way ofa metering orifice 64 which is controlled in part by a metering rod 66.

Air is bled into the idle fuel system in a manner substantially the sameas that described above with respect to the main fuel system. Referringto FIG. 6, it will be seen that idle fuel is drawn by a passage 70 fromthe main fuel passage 57 of FIG. 5 and passes upwardly through a diptube 71 and thence, through a restriction 72 where it is mixed with aquantity of air supplied by way of orifice 73, the resultant mixturethen passes through restriction 74 where additional air can be added byway of restriction 75, thence downwardly by way of passage 77 to across-passage 78 which terminates in the bore of the carburetor adjacentthe throttle valve.

Communication with the compensating unit is established by way ofrestriction 79 and conduit 18 which connects with the compensating unitand is supplied with metered air by way of metering pin 80 which isbiased by way of a spring 81 in an outwardly direction and which, aspreviously mentioned, is adjusted by way of adjustment screw 46 carriedon plate 40. It is to be mentioned that both metering pins 52 and 80 areprovided with a taper such that as plate 40 moves upwardly, greaterquantities of air are admitted into conduits l6 and 18 thereby reducingthe quantity of fuel discharged by the main and idle fuel systems.

A final engine function that is accomplished by the compensating unit ofthe invention is illustrated by two different embodiments in FIG. 7. Inthat Figure there are shown two vacuum responsive devices in the form ofdiaphragm units. One of these controls the step-up by which thecarburetor is caused to provide enrichment fuel under heavy-load orwide-open throttle conditions and the other is a diaphragm motor such ascan be used to control spark advance or, in some instances, the shiftmechanism of an automatic transmission. It is to be recognized that anyor all of these vacuum responsive units could comprise a piston insteadofa diaphragm mechanism.

As shown in FIG. 7, conduit is attached to the carburetor by means of atube 85 which intersects a passage 86 in the throttle flange of thecarburetor. Passage 86 enters the bore of the throttle of the carburetorbelow the throttle valve 88. By means of a branch passage. conduit 86communicates with a space 90 below the diaphragm ofa diaphragm-typeaccelerating pump. The diaphragm is shown at 91 and is attached bysuitable retaining means to a stem 92 which is biased in an upwardlydirection by spring 93. A cavity 94 on the upper side of the diaphragmis utilized for the acceleration fuel provided by the diaphragm pump. Inthis instance, the inlet and outlet of fuel to the space 94 is not shownfor convenience sake, Stem 92 is provided with a carrier bar 96 whichsupports the metering rod 66. In the normal operation of the pump,manifold vacuum acting in space 90 pulls the diaphragm down and thispermits the pumping space 94 to fill with fuel while at the same timedrawing the metering rod 66 down into the metering jet 64 to reduce theannular clearance between the tuper of the metering rod and the interiorof the jet. Upon a reduction of vacuum, as would come about ifthrottleBB were opened more widely, spring 93 overcomes the vacuum and causesthe diaphragm to move upwardly so that fuel is discharged into thecarburetor front the accelerating pump and at the same time, meteringrod 66 is drawn up to provide a greater annular clearance, thusproviding additional fuel to the carburetor for enrichment purposes.This is commonly referred to as step-up.

Referring now to FIG. 4, it will be seen that conduit 20 communicateswith air metering means in the form of a metering rod 100 which isprovided at its lowermost extremity with a reverse taper meteringsection. As with the metering rods described earlier, rod 100 moves upand down under the influence of biasing spring 102 and carrier plate 40.Adjustment screw 48 makes final calibration adjustments of therelationship of metering rod 100 with its metering orifice. Air isprovided from the interior of compensating unit 10 to the metering zoneby way of a passage 104.

Returning to FIG. 7, there is shown an additional engine controlfunction connected by a pipe to passage 86. Pipe 110 communicates with avacuum motor 112 which is shown as a diaphragm unit but which might be apiston-type device. Diaphragm unit 112 is provided with a diaphragm 114biased in a direction away from the source of vacuum by a spring 116. Anoperating arm 118 is attached to the opposite side from the biasingspring to the diaphragm. Arm 118 can be connected to any selectedfunction, as for example, the spark advance of the ignition distributoror to the shift mechanism of an automatic transmission. Each of theseengine functions may be required to alter operating characteristics asthe vehicle is driven into changing conditions of altitude ortemperature. Thus, the vacuum motor 112 which receives a controlledvacuum signal which is dependent upon the altitude and/or temperaturecan be made to function in a desired and programmed manner. Althoughmotor 112 is shown connected to the same system as the accelerator pumpand step-up of the carburetor, it could be divorced from that system aswould be obvious merely through the provision of a separate air meteringelement corresponding to element 100 and a separate source of vacuumtogether with a suitable connecting passage corre' sponding to passage20.

The foregoing description has described a system primarily for use in asingle barrel carburetor in which the altitude/temperature compensatingunit is separated from the carburetor and engine and connected to thenecessary components by means of flexible tubes or hoses. it will beapparent that to the extent the altitude/temperature unit controlscarburetor functions, the unit can be integrated with the carburetorstructure and the various hoses replaced with integral passages in thecarburetor body structure. In such an embodiment, the only remotelocations connected by tubes or hoses would be to the other enginefunctions such as distributor vacuum motors and/or automatictransmission control motors.

In the remaining figures of drawing, the basic concepts of the inventionare applied to a four-barrel carburetor and, for the most part, thesesame concepts would be true of a two-barrel carburetor. In making thedescription of the four-barrel carburetor. numbers similar to that usedin the single barrel carburetor will be used, excepting that all numberswill be three-digit numbers in place ofmostly two-digit numbers used earlier. as for example. the number 14 will become number 214, 20 willbecome 220. etc. A further difference between the four-barrel embodimentand the single barrel embodiment is that the passageways which wereformerly separate conduits, such as flexible rubber tubing, now arepassages formed or drilled integrally in the carburetor body and thealtitude/temperature compensation unit is also mounted directly on thecarburetor body.

Referring now to FIG. 8, there is shown the base of a compensating unit220 mounted on the body of a four-barrel carburetor 212. A cover 223 isprovided for covering up the operative mechanism of the compensatorunit. The four-barrel carburetor 212 has two primary barrels and twosecondary barrels. The primary barrels are each equipped with an idlefuel system and a main fuel system while the secondary barrels have onlya single main fuel system each. Since each of the fuel systems can bemanaged by single metering pin, the unit 210 duplicates the meteringcapability of the compensating unit 10 of FIG. 1 with the addition ofone additional capability for the secondary fuel nozzles. A passage 214communicates at one end with the air horn of the carburetor and, thus,with the space inside the air cleaner and its other end with theinterior of compensating unit 210. In this fashion. clean air issupplied for all air metering functions. This last is shown also in FIG.10.

Also shown in FIG. 8 is a passageway 216 which extends from the interiorof unit 210 to a branch extending to each of the two main nozzle wellsindicated at 256. Similarly, a passage 218 is branched to extend to thetwo idle fuel passages 277. A passage 213 extends to a branching pointwhere it separates and branches out to secondary fuel wells 215. It isto be remembered that all of the fuel passages and fuel systems in thefourbarrel version are substantially similar to the single barrelversion shown in FIGS. 1 through 7. Principal difference being thesecondary fuel nozzle and secondary fuel well which are at least similarto the primary fuel nozzle and well.

Multiple barrel carburetors are normally provided with a pair ofmetering rods 266 which cooperate with a metering jet similar to jet 64of FIG. 5. In the embodiment shown. the metering rod 266 is controlledin part by a vacuum actuated piston 291 which receives vacuum by way ofpassage 286. The passage 286 communicates with the intake manifold at apoint beneath the throttle valve and communicates also with a passage220 which terminates in the compensating unit 210 where an air meteringpin controls the quantity of air that is admitted into the vacuumpassage 286 to regulate the vacuum therein.

Referring now to FIG. 13, vacuum piston 291 can also be forced into anupward position by means of a rod 300 which is driven by a leaf 302which in turn is driven by a cam 304 on throttle shaft 306. Thus, whenthrottle shaft 6 is rotated in a direction to open the throttle, the cam304 will move leaf 302 upwardly to in turn move rod 300 which in turnwill lift the metering pin 266 the desired amount. In this manner,additional fuel can be delivered to the main nozzles of the primarybarrel as the throttles are opened. On the other hand, if there is asudden loss of manifold vacuum. as sometimes occurs, piston 291 isallowed to rise upwardly and this in turn lifts the metering rod 266 toprovide the fuel enrichment usually desired under these conditions.

Referring now to FIGS. 14 through 18, the compensating unit 210 is quitesimilar to the unit 10 of FIGS. 2. 3 & 4. and contains all of the samefeatures. although housed somewhat differently. Air conduits 213, 214.2l6, 218 and 220 are connected to a carburetor as shown in FIG. 8. Plate240 is hinged at 242 and carries a plurality of adjustment screws.Adjustment screw 236 makes any needed corrections or adjustments to thecontact with barometric and/or temperature capsule 230. Adjustmentscrews 244, 246 and 248 are provided to position metering pins in thesame fashion as screws 44, 46 and 48 of FIGS. 3 and 4. Additionally,biasing adjustment screw 250 adjusts tension on a spring in the samemanner as does screw 50 of FIG. 3. A further metering screw 245 isprovided to adjust the position of the metering pin which controls theair delivered to the secondary fuel nozzles by way of conduit 13 and, asex plained earlier, this is in the same manner as the air delivered tothe primary main nozzles.

In FIGS. 8 through 19, the 200 series of numbers corresponds as nearlyas possible with the below 100 series of numbers in FIGS. 1 through 7.It is believed unnecessary to give a detailed description of the variousfeatures of FIGS. 8 through 19 and a brief description is believedsufficient.

FIG. 14 corresponds roughly to FIG. 2, with the exception that it isconfigured for a multibarrel carburetor. FIG. 15 corresponds to FIG. 3.FIG. 16 illustrates a means by which spring 251 can be adjusted by meansof screw 250 and also by means of a screw 253 which adjusts the bottomend of the spring 251. In a similar manner, spring 251 can be adjustedby an external means, which, for example, could be a temperature sensor255 in communication with an exhaust manifold 257 which by means of athermal motor 259, can adjust an arm 261 which in turn will adjust thespring 251. Thus, as exhaust temperature changes, the bias on spring 251will be adjusted in accordance with engine operation to put a bias onplate 240 to thereby change the quantity of air bled into the fuelmetering systems in accordance with engine demands. FIG. 11 is similarto FIG. 5, excepting that the fuel nozzle 271 is a secondary main fuelnozzle and in all other respects, the air bleed into the nozzle issimilar to that of FIG. 5. FIG. I3 is similar to the righthand portionof FIG. 7 in that it shows a means for raising or lowering a meteringrod 266 in accordance with the position of the throttle. 306 is theprimary throttle shaft and 304 is a cam on that shaft. The cam in turnmoves a lever 302 which raises and/or lowers a rod 300 which is indirect connection with metering rod 266.

FIGS. 17 and 18 illustrate metering pins moved by plate 240. In FIG. 17metering pin 320 functions in the same manner as metering pin 100 ofFIG. 4 to reduce the quantity of air flowing through a passage 322 whichcommunicates with a motor such as diaphragm motor 112 of FIG. 7. In asimilar manner. metering rod 280 of FIG. 18 functions much the same asmetering rod of FIG. 4 to increase the amount of air bled into the fuelsystem when plate 240 rises under the influence of reduced barometricpressure or increased temperature and rod 280 can be adjusted as desiredby screw 250 and its associated nut.

From the foregoing it can be seen that a capsule sensitive to barometricpressure and/or temperature can be utilized to adjust air bleeds intovarious operative functions of an engine to thereby control saidfunctions as a result of changes in atmospheric pressure and/ortemperature. In general. it can be said that whether the engine beequipped with a one-barrel. two-barrel. or four-barrel carburetor. theair bleeds can be compensated in such a manner that, with increasingaltitude or decreasing barometric pressure, the fuel supplied to thecarburetor will be reduced in accordance with such change and otheroperative functions of the vehicle such as transmission shifts and/orspark advance or retard can be accomodated in such a manner as toachieve optimum operation of the engine and vehicle.

I claim:

1. In an internal combustion engine having a plurality of enginefunctions operable by the suction created by the natural aspiration ofsaid engine during running condition. the improvement comprising;

an attachment connected to said engine communicating on one side withambient air and on another side with at least one suction controlledpassage leading to at least one engine function controlling means,

said attachment including control means responsive to barometric and/ortemperature changes to change a dimension of said control means,

said control means being connected to a metering means adapted to admitsaid ambient air to said suction controlled passage in accordance withchanges in said dimension, and

the said suction controlled passage terminating at an end thereof in thevacuum chamber of a vacuum motor.

2. Apparatus according to claim I in which said metering means comprisesa metering rod moveable by said control means, said metering meansfurther including a metering jet, said metering jet communicating on oneside with ambient air and on the other side with said suction controlledpassage, said suction controlled passage communicating at another endthereof with a source of vacuum.

3. Apparatus according to claim 2 further including a tapered portion onthe end of said metering rod in said metering jet, tapered portionincreasing in diameter as said rod is withdrawn from said jet.

4. Apparatus according to claim 3 in which said vacuum motor is one of;a vacuum motor for providing fuel enrichment to a carburetor forsupplying a fuel-air mixture to said internal combustion engine, avacuum motor for controlling the spark advance of a spark ignitionsystem for said internal combustion engine, and a vacuum motor forcontrolling the gear selection of an automatic transmission for drivinga vehicle powered by said engine.

1. In an internal combustion engine having a plurality of enginefunctions operable by the suction created by the natural aspiration ofsaid engine during running condition, the improvement comprising; anattachment connected to said engine communicating on one side withambient air and on another side with at least one suction controlledpassage leading to at least one engine function controlling means, saidattachment including control means responsive to barometric and/ortemperature changes to change a dimension of said control means, saidcontrol means being connected to a metering means adapted to admit saidambient air to said suction controlled passage in accordance withchanges in said dimension, and the said suction controlled passageterminating at an end thereof in the vacuum chamber of a vacuum motor.2. Apparatus according to claim 1 in which said metering means comprisesa metering rod moveable by said control means, said metering meansfurther including a metering jet, said metering jet communicating on oneside with ambient air and on the other side with said suction controlledpassage, said suction controlled passage communicating at another endthereof with a source of vacuum.
 3. Apparatus according to claim 2further including a tapered portion on the end of said metering rod insaid metering jet, tapered portion increasing in diameter as said rod iswithdrawn from said jet.
 4. Apparatus according to claim 3 in which saidvacuum motor is one of; a vacuum motor for providing fuel enrichment toa carburetor for supplying a fuel-air mixture to said internalcombustion engine, a vacuum motor for controlling the spark advance of aspark ignition system for said internal combustion engine, and a vacuummotor for controlling the gear selection of an automatic transmissionfor driving a vehicle powered by said engine.